pkg/test: cleanup imports

lib/src/backend/suite.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'group.dart';
 import 'metadata.dart';
 import 'operating_system.dart';
-import 'group.dart';
 import 'test.dart';
 import 'test_platform.dart';
 
 /// A test suite.
 ///
 /// A test suite is a set of tests that are intended to be run together and that
 /// share default configuration.
 class Suite {
   /// The platform on which the suite is running, or `null` if that platform is
   /// unknown.
@@ skipping 46 matching lines @@
   /// Returns a new suite with all tests matching [test] removed.
   ///
   /// Unlike [GroupEntry.filter], this never returns `null`. If all entries are
   /// filtered out, it returns an empty suite.
   Suite filter(bool callback(Test test)) {
     var filtered = group.filter(callback);
     if (filtered == null) filtered = new Group.root([], metadata: metadata);
     return new Suite(filtered, platform: platform, os: os, path: path);
   }
 }